From fed70f3ac817ed4943a230cb901fcd65dc6fdd0c Mon Sep 17 00:00:00 2001 From: Maël Gassmann Date: Fri, 11 Jun 2021 20:55:12 +0200 Subject: [~] First totaly functional Calculator, reorganised the files, verified and added error messages --- .../main/java/ch/bfh/parser/ExpressionParser.java | 36 ++++++++++------------ .../src/main/java/ch/bfh/parser/FactorParser.java | 15 ++++----- .../src/main/java/ch/bfh/parser/Parser.java | 7 ++--- .../main/java/ch/bfh/parser/ParserException.java | 8 +++++ .../main/java/ch/bfh/parser/StatementParser.java | 13 ++++---- .../src/main/java/ch/bfh/parser/TermParser.java | 13 ++++---- 6 files changed, 49 insertions(+), 43 deletions(-) create mode 100644 calculator-java/src/main/java/ch/bfh/parser/ParserException.java (limited to 'calculator-java/src/main/java/ch/bfh/parser') diff --git a/calculator-java/src/main/java/ch/bfh/parser/ExpressionParser.java b/calculator-java/src/main/java/ch/bfh/parser/ExpressionParser.java index 3ec0194..e68983b 100644 --- a/calculator-java/src/main/java/ch/bfh/parser/ExpressionParser.java +++ b/calculator-java/src/main/java/ch/bfh/parser/ExpressionParser.java @@ -1,22 +1,15 @@ package ch.bfh.parser; -import ch.bfh.CalculatorLexer; -import ch.bfh.Token; -import ch.bfh.exceptions.ParserException; - +import ch.bfh.lexer.CalculatorLexer; +import ch.bfh.lexer.Token; import java.util.ArrayList; -public class ExpressionParser extends Parser { +class ExpressionParser extends Parser { protected ArrayList parsers = new ArrayList<>(); protected ArrayList ops = new ArrayList<>(); private boolean isParenthesised = false; - public ExpressionParser(CalculatorLexer cl) { - this.cl = cl; - parse(); - } - protected ExpressionParser(CalculatorLexer cl, Token lastToken, boolean isParenthesised) { this.cl = cl; this.lastToken = lastToken; @@ -31,8 +24,8 @@ public class ExpressionParser extends Parser { token = lastToken; else token = cl.nextToken(); - Parser l = null; - Parser r = null; // left and right expressions + TermParser l = null; + TermParser r = null; // left and right Terms Token op = null; // operation of the current l and right expressions loop: @@ -48,9 +41,9 @@ public class ExpressionParser extends Parser { op = token; this.ops.add(op); }else if (l == null) - throw new ParserException("Factor cannot start with '+'."); + throw new ParserException("Redundant use of '+' is forbidden."); else - throw new ParserException("Invalid use of '+' was found in the Expression."); + throw new ParserException(token, "repetition of operator -> a term was expected."); break; case Token.SUB: if (l != null && op == null) { // if the '-' sign is between two term (op) @@ -82,14 +75,19 @@ public class ExpressionParser extends Parser { break loop; } else throw new ParserException("No matching opening parenthesis were found."); - default: - //TODO - Replace default by each individual case - throw new ParserException("Malformed Expression."); + case Token.MUL: + case Token.DIV: + throw new ParserException(token,"a term was expected."); + case Token.EQU: + case Token.LET: + throw new ParserException("The inputted token '"+token.str+"' can only be placed in a variable declaration context (let var = Expression)."); + case Token.END: + throw new ParserException("The keyword 'exit' can only be placed at the beginning of an expression."); } token = cl.nextToken(); } if (op != null && r == null) - throw new ParserException("Missing expression after last operation '"+op.str+"'"); + throw new ParserException("Missing term after the last operator '"+op.str+"'."); } @Override @@ -111,4 +109,4 @@ public class ExpressionParser extends Parser { } return result; } -} +} \ No newline at end of file diff --git a/calculator-java/src/main/java/ch/bfh/parser/FactorParser.java b/calculator-java/src/main/java/ch/bfh/parser/FactorParser.java index 8bb5ef7..fd54cf4 100644 --- a/calculator-java/src/main/java/ch/bfh/parser/FactorParser.java +++ b/calculator-java/src/main/java/ch/bfh/parser/FactorParser.java @@ -1,8 +1,7 @@ package ch.bfh.parser; -import ch.bfh.CalculatorLexer; -import ch.bfh.Token; -import ch.bfh.exceptions.ParserException; +import ch.bfh.lexer.CalculatorLexer; +import ch.bfh.lexer.Token; class FactorParser extends Parser { @@ -72,9 +71,11 @@ class FactorParser extends Parser { lastToken = token; else throw new ParserException("Missing expression before closing the parenthesis."); break loop; - default: - //TODO - Replace default by each individual case - throw new ParserException("Malformed Expression."); + case Token.EQU: + case Token.LET: + throw new ParserException("The inputted token '"+token.str+"' can only be placed in a variable declaration context (let var = Expression)."); + case Token.END: + throw new ParserException("The keyword 'exit' can only be placed at the beginning of an expression."); } token = cl.nextToken(); } @@ -91,4 +92,4 @@ class FactorParser extends Parser { return value * (-1); return value; } -} +} \ No newline at end of file diff --git a/calculator-java/src/main/java/ch/bfh/parser/Parser.java b/calculator-java/src/main/java/ch/bfh/parser/Parser.java index 333b942..6a03fe1 100644 --- a/calculator-java/src/main/java/ch/bfh/parser/Parser.java +++ b/calculator-java/src/main/java/ch/bfh/parser/Parser.java @@ -1,14 +1,13 @@ package ch.bfh.parser; -import ch.bfh.CalculatorLexer; -import ch.bfh.Token; - +import ch.bfh.lexer.CalculatorLexer; +import ch.bfh.lexer.Token; import java.util.HashMap; import java.util.Map; abstract class Parser{ - protected static Map variables = new HashMap<>(); //'Persisted' Expressions when 'let' token was specified + protected static Map variables = new HashMap<>(); //Persisted Expressions aka variables protected CalculatorLexer cl; protected Token lastToken; diff --git a/calculator-java/src/main/java/ch/bfh/parser/ParserException.java b/calculator-java/src/main/java/ch/bfh/parser/ParserException.java new file mode 100644 index 0000000..a85e3b2 --- /dev/null +++ b/calculator-java/src/main/java/ch/bfh/parser/ParserException.java @@ -0,0 +1,8 @@ +package ch.bfh.parser; + +import ch.bfh.lexer.Token; + +public class ParserException extends RuntimeException { + public ParserException(String s) { super(s); } + public ParserException(Token token, String s) { super("Last read token: '"+token.str+"', "+s); } +} \ No newline at end of file diff --git a/calculator-java/src/main/java/ch/bfh/parser/StatementParser.java b/calculator-java/src/main/java/ch/bfh/parser/StatementParser.java index c85398b..482ef34 100644 --- a/calculator-java/src/main/java/ch/bfh/parser/StatementParser.java +++ b/calculator-java/src/main/java/ch/bfh/parser/StatementParser.java @@ -1,8 +1,7 @@ package ch.bfh.parser; -import ch.bfh.CalculatorLexer; -import ch.bfh.Token; -import ch.bfh.exceptions.ParserException; +import ch.bfh.lexer.CalculatorLexer; +import ch.bfh.lexer.Token; public class StatementParser extends Parser{ @@ -27,15 +26,15 @@ public class StatementParser extends Parser{ switch (token.type) { case Token.LET: if (lastToken != null) - throw new ParserException("The keyword 'let' cannot be placed anywhere else than at the beginning of an expression."); + throw new ParserException("The keyword 'let' can only be placed at the beginning of an expression."); break; case Token.EQU: if (lastToken == null || lastToken.type != Token.LET || variableName == null) - throw new ParserException("The inputted token '=' can only be placed in a variable declaration context (let variable = Expression)."); + throw new ParserException("The token '=' can only be placed in a variable declaration context (let var = Expression)."); break; case Token.END: if (lastToken != null) - throw new ParserException("The keyword 'exit' cannot be placed anywhere else than at the beginning of an expression."); + throw new ParserException("The keyword 'exit' can only be placed at the beginning of an expression."); else System.exit(0); case Token.ID: @@ -58,7 +57,7 @@ public class StatementParser extends Parser{ if (lastToken == null) return; if (lastToken.type == Token.LET || lastToken.type == Token.EQU) - throw new ParserException("Incomplete variable declaration"); + throw new ParserException("Incomplete variable declaration. Expected: let var = Expression."); } @Override diff --git a/calculator-java/src/main/java/ch/bfh/parser/TermParser.java b/calculator-java/src/main/java/ch/bfh/parser/TermParser.java index 9a97659..9e49fa8 100644 --- a/calculator-java/src/main/java/ch/bfh/parser/TermParser.java +++ b/calculator-java/src/main/java/ch/bfh/parser/TermParser.java @@ -1,8 +1,7 @@ package ch.bfh.parser; -import ch.bfh.CalculatorLexer; -import ch.bfh.Token; -import ch.bfh.exceptions.ParserException; +import ch.bfh.lexer.CalculatorLexer; +import ch.bfh.lexer.Token; class TermParser extends ExpressionParser { @@ -61,9 +60,11 @@ class TermParser extends ExpressionParser { case Token.PAR: // Going as high as possible --> possibly the end of an expression created by a Factor :) lastToken = token; break loop; - default: - //TODO - Replace default by each individual case - throw new ParserException("Malformed Expression."); + case Token.EQU: + case Token.LET: + throw new ParserException("The inputted token '"+token.str+"' can only be placed in a variable declaration context (let var = Expression)."); + case Token.END: + throw new ParserException("The keyword 'exit' can only be placed at the beginning of an expression."); } token = cl.nextToken(); } -- cgit v1.2.3